Method For Producing A Container Body

ABSTRACT

The method forms a blank into the container body. A disc-shaped blank is punched out of a metal sheet. Following the punching process, the two edges of the blank are compressed. The disc-shaped blank thus obtains a symmetrical shape. With any of its two flat sides, the blank can be transported into a forming position, from which it is then formed into the container body. The edges obtain an accurately predetermined shape and can thus be arranged more easily in the desired forming position. Preferably, both edges are machines simultaneously in response to compressing the two edges of the blank.

BACKGROUND OF THE INVENTION

The invention relates to a method for producing a container body, which is produced from a blank, which is identified as round blank, in a seam and joint-free manner. For example, the container body encompasses a cylindrical container wall, which, at one end, merges axially into a container part, which closes the container body, such as a container bottom. The container body, which is to be produced, can thus be closed axially at one end by means of the container part, or can also encompass an opening at both ends. The container body is open at at least one axial end. Such container bodies can be produced by means of impact extrusion, for example, so as to produce tubes, cans or the like of metal, for example aluminum, or of a metal alloy. The shape of the container body can vary as a function of the design of the die and of the stamp.

An extrusion press for producing such container bodies is known from DE 1 402 784 A, e.g.. Round blanks or plates are fed to the extrusion press and are positioned between the die and a stamp. This stamp presses the plate into the die. The material thereby flows opposite to the direction of motion of the stamp around the latter and thereby also flows out of the die, wherein forming takes place between the container body. As an alternative to this backward impact extrusion, forward impact extrusion methods or combined forward-backward impact extrusion methods are also known, in the case of which the material also flows exclusively or additionally, respectively, in the direction of motion of the stamp.

A different method for producing a container body by means of deep drawing-ironing is described in DE 2 308 132 or DE 10 2010 000 094 A1, for example. Initially, round blanks are punched out of a sheet metal plate. In an ironing station, said round blanks are subsequently pulled through a die with the help of a drawing punch and are thereby formed.

Impact extrusion methods for producing cans are known and have been used for a long time. In the case of these methods, however, it is necessary to position the punched-out disc-shaped blanks, which are also identified as round blanks, in a desired orientation upstream of the extrusion presses so as to form the container body. This is necessary, because the blanks or round blanks encompass a punching burr after the punching. On principle, this punching burr does not interfere with the production of the container body, because the edge of the container wall located opposite the container bottom is cut off in any event after forming the disc-shaped blank into the container body. Unevenness at this edge, which is formed by the punching burr, is thus unproblematic.

However, this requires the orientation of the blank or of the round blank, respectively, prior to the impact extrusion such that the flat side, which encompasses the punching burr, is assigned to the axially open end of the container body, which is to be produced. In response to an incorrect orientation of the blank prior to the impact extrusion, the punching burr can lead to holes in the container wall or to so-called laminations in the wall. This is the case, if the punching burr is pressed into or through the die, respectively, opposite the flow direction of the material. This problem has been known for a long time. Today, it is solved in that a forming takes place at the same time the disc-shaped blank or round blank, respectively, is punched out in response to which the round blank is bent. This is identified as cambering. By bending the blank, the latter is formed unevenly on its two sides. This is why a sorting is possible in response to the feeding or transporting, respectively, of the blanks to the forming station, so that the blank comprising the punching burr thereof always encompasses the desired orientation in flow direction of the material. Such a sorting extensive. Errors, which in turn entail errors in response to the forming of the blank into the container body, can also occur in response to the sorting.

In response to the deep drawing-ironing of round blanks into container bodies, the latter are on principle seized by means of a gripping device and are placed between the drawing stamp and the die. It can occur thereby that round blanks, which lie flat on top of one another, stick to one another and that two round blanks are grabbed inadvertently and are fed to the press. This leads to errors.

SUMMARY OF THE INVENTION

It can thus be considered to be the object of the instant invention to provide for a method, which is less extensive and which avoids or at least significantly reduces errors in response to the forming of the blank into the container body.

According to the invention, this object is solved by means of a method comprising the features of patent claim 1.

According to the invention, a disc-shaped blank, which preferably comprises a circular contour, is punched out of a metal sheet. In the case of a circular contour, the blank can also be identified as round blank. Following the punching process, the two edges of the blank are compressed. Due to this compression process, a punching burr, which might be present, is removed. The disc-shaped blank thus obtains a symmetrical shape opposite a symmetrical plane, which runs centrally between the two flat sides of the blank. By compressing the two edges and due to the resulting symmetrical design of the blank, a subsequent sorting is superfluous. With any of its two flat sides, the blank can be transported into a forming position, from which it is then formed into the container body, for example in an impact extrusion process. By compressing the two ring-shaped edges, a calibration of the blank is also attained. Irregularities of the punching process have been removed. The edges obtain an accurately predetermined shape and can thus be arranged more easily in the desired forming position, which in turn, prevents errors in response to the forming process. The transporting or feeding, respectively, of the disc-shaped blanks to the forming station is also simplified, because all blanks, except for slight process tolerances in response to the compression, encompass the same shape and because irregularities of the punching process have been removed. The blanks, which are to be transported, are flat and do not encompass an irregular punching burr.

The forming the blank into the container body can also take place by means of impact extrusion, for example. In the forming position, the blank can be arranged between a stamp in the upper tool of the press and a die in the lower tool of the press. In the forming position, the blank preferably rests with one of its two flat sides against a contact surface of the forming press, which surrounds the die in a ring-shaped manner, for example.

Preferably, both edges are machines simultaneously in response to compressing the two edges of the blank. A high flow and an efficient production process can be reached through this. Machines, for example, which can be used for rimming and/or coining coins, are suitable for compressing the two edges of the blank. Such machines are available on the market and can be used very easily for the method according to the invention. Even though the blank for the container body production preferably consists of aluminum, it turned out that the machines, which are used for rimming coins, are also suitable for rimming the round blanks made of aluminum, which are punched out for the container body production. Aluminum is a very soft material. It was nonetheless possible to compress the edges so as to obtain the desired shape, without negatively influencing the cylindrical, disc-shaped design of the round blank.

During the compression, the peripheral surface of the blank, which is bordered by the two edges, which are to be compressed, preferably rolls off of a compression tool. The two edges are compressed and are brought into the desired shape by means of a pressure forming process. The shape of the round blank or of the blank, respectively, in the area of the edges and of the peripheral surface is predetermined by the compression tool. In the case of a preferred exemplary embodiment, a compressed groove, in which the round blank rolls off with the peripheral surface, is present in the compression tool for this purpose.

By compressing the round blank, a radius, a circumferential bezel or also a circumferential border can be formed at the two edges. Such a border can serve the purpose, for example, to simplify the positioning of the round blank in the forming position.

Advantageous embodiments of the method follow from the dependent patent claims as well as from the description. The description is limited to significant features of the invention as well as to other structural conditions. Preferred exemplary embodiments of the invention are explained by means of the drawing.

IN THE DRAWINGS

FIG. 1 shows a strip-shaped sheet metal plate in a schematic illustration as basic material for punching out round blanks,

FIG. 2 shows a schematic, block-diagrammatic illustration of the punching process,

FIG. 3 shows a partially cut illustration of the border area of a round blank after being punched out,

FIG. 4 shows a first exemplary arrangement for compressing the edges of the round blank in partial illustration,

FIG. 5 shows a second exemplary arrangement for compressing the edge of the round blank in partial illustration,

FIGS. 6 to 8 show a partially cut illustration of a respective round blank after compression comprising different edge shapes and

FIGS. 9 to 11 show an exemplary, highly schematized illustration of an impact extrusion process.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a method for producing a container body comprising a hollow-cylindrical shape, for example, which, in the case of the preferred exemplary embodiment, is open at an axial end and which, at the other axial end, merges in a seam and joint-free manner into a container part, which closes the container body. As an alternative, a container body, which is open at both axial ends, can also be produced by means of impact extrusion. The container body is produced from a disc-shaped, cylindrical blank 10. In the case of the instant method, the blank has a circular contour and will thus be identified hereinbelow as round blank 10.

In a first method step, the round blanks 10 are punched out of a metal sheet 11, which, according to the example, consists of aluminum. The metal sheet 11 can be unwound from a roll as strip-shaped material and can be punched out with the help of a punching tool 12, as it is illustrated schematically in FIG. 2.

After the punching, the round blank 10 encompasses a punching burr 14 at one of its two flat sides 13. This punching burr 14 is irregular and causes an asymmetrical design of the round blank 10.

After punching out the round blank 10, a compression process is carried out to remove the punching burr 14 as well as to produce a symmetrical shape opposite a symmetrical plane S, which runs centrally between the two flat sides 13. The two ring-shaped edges 15, which border the peripheral surface 16 of the round blank 10, are compressed thereby and are brought into a desired shape. Different exemplary embodiments of the round blanks 10 are illustrated in FIGS. 6 to 8, wherein each round blank 10 encompasses a different edge shape. Due to the compression, a radius R, a bezel F or a circumferential projection can be formed at an edge 15 for forming a border V. In the case of the exemplary embodiment illustrated in FIG. 6, the projection or border V, respectively, encompasses a rounded shape and is closed in a ring-shaped manner. It projects beyond the respective adjoining flat side 13 and merges continuously into the peripheral surface 16. The compressed edge 15 of the round blank 10 can merge into the peripheral surface 16 and/or the assigned flat side 13 either rounded or so as to be bordered by edges. However, the edge 15 does not project beyond the cylinder jacket surface defined by the peripheral surface 16 in any of the exemplary embodiments.

FIGS. 4 and 5 illustrate compression devices 17 for compressing the two edges 15 of the round blank 10 in a schematic manner. The compression device 17 encompasses a compression tool 18 comprising a compressed groove 19. The compressed groove 19 runs along a segment of a circle. Accordingly, the compression tool 18 can encompass a ring segment-like contour. At a distance to the compression tool 18 and to the compressed groove 19, a drive wheel 20 comprising a drive groove 21 is arranged coaxially to the compressed groove 19. For compression purposes, the round blank 10 is accommodated in the drive groove 21 of the drive wheel 20 and is rolled off along the compressed groove 19 of the compression tool 18. To compress the entire edge 15, the length of the compressed groove 19 corresponds at least to the periphery of the two edges 15 of the round blank 10. The cross sectional shape of the compressed groove 19 determines the shape of the edge 15 after the compression process. In response to the compression, the round blank 10 is clamped between the drive wheel 20 and the stationary compression tool 18, whereby the two edges 15 form in the compressed groove 19 and adapt to the shape of the compressed groove 19.

The two exemplary embodiments of the compression devices 17 in FIGS. 4 and 5 operate according to the same principle. In both cases, the drive groove 21 and the compressed groove 19 are arranged coaxially to the drive axle of the drive wheel 20. In the case of the exemplary embodiment according to FIG. 1, the radius of the compressed groove 19 is larger than the radius of the drive groove 21. In the case of this first exemplary embodiment, the compressed groove 19 encompasses a larger distance to the drive axle of the drive wheel 20, than the drive grove 21. In contrast, the drive groove 21 and the compressed groove 19 are arranged at an axial distance to one another and have the same distance to the drive axle in the case of the second exemplary embodiment according to FIG. 5.

Further modifications of the exemplary embodiments of the compression device 17 are possible. For example, as a modification of the first exemplary embodiment according to FIG. 4, the compression tool 19 could be arranged within the drive wheel 20, so that the distance of the compressed groove 19 to the drive axle is smaller than the distance of the dive groove 21. In the case of all of the exemplary embodiments, the compressed groove 19 and the drive groove 21 are oriented so as to be aligned with one another, so that the round blank 10 engages with the compressed groove 19 as well as with the drive groove 21 and can roll off in both groves 19, 21.

After compression, the round blanks 10 are finally transported to a forming device 22, which is shown in FIGS. 9 to 11 in a schematic and highly simplified manner. For forming purposes, the round blanks 10 are positioned in a forming position P in a die 23 of the forming device 22. The forming device 22 further includes a stamp 24, which can be moved along its longitudinal stamp axis relative to the die 23. At a distance to the die 23, provision is made for a wiping device 25, which encompasses an opening 26, through which the stamp 24 projects. In the area of the opening, the wiping device 25 can rest against the stamp 24 or can form a small gap to the jacket surface of the stamp 24, which is smaller than the wall thickness of a container body 27 formed from the round blank 10.

A forming device 22 for carrying out a backward impact extrusion process is illustrated by means of FIGS. 9 to 11 in an exemplary manner. As a modification, the method according to the invention can also be used for forming devices 22, which carry out a forward impact extrusion process or a combination of backward and forward impact extrusion process.

On the side facing the stamp 24, the die 23 is open for carrying out the backward impact extrusion method as is illustrated schematically in FIGS. 9 to 11. After inserting the round blank 10 into the recess of the die 23, the stamp 24 is moved towards the die 23. After resting against the round blank 10, the round blank is pressed between the die 23 and the stamp 24, whereby the material initially deforms between the stamp 24 and the die 23 and thereby flows out of the die 23 along the outer stamp surface opposite the direction of motion of the stamp 24, as is illustrated in FIG. 10.

After the forming process has ended, the stamp 24 is moved back away from the die 23. In response to this backward movement, it wipes the container body 27, which was produced, on the wiping device 25. The container body 27 is then removed from the forming device 22 and a new round blank 20 is inserted into the die 23. The backward impact extrusion method for producing the container body 27 then starts anew.

The invention relates to a method for producing a container body. A disc-shaped round blank 10 comprising a circular cylindrical contour is first punched out of a metal sheet, in particular an aluminum sheet. The two circular edges 15 of the round blank 10 are then formed into a predetermined desired shape in a compression process. During said compression process, the peripheral surface 16 of the round blank 10 bordered by the two edges 15 rolls off in a compressed groove 19 of a compression tool 18, said compressed groove determining the edge shape. This produces a symmetrical shape opposite a symmetrical plane S, which runs centrally between the two flat sides of the round blank 10. The round blank 10 can therefore be fed to a forming device 22 without the need for sorting and orientation. The round blank 10 can thereby be turned towards a stamp 23 or a forming die 24, respectively, with any one of its two flat sides 13. It is thereby possible for the round blank 10 to be fed in two different positions into the forming position P of the forming device 22 without the forming process or the container body being negatively influenced as a result.

LIST OF REFERENCE SIGNS

-   10 blank, round blank -   11 metal sheet -   12 punching tool -   13 flat side of the round blank -   14 punching burr -   15 edge of the round blank -   16 peripheral surface -   17 compression device -   18 compression tool -   19 compressed groove -   20 drive wheel -   21 drive groove -   22 forming device -   23 die -   24 stamp -   25 wiping device -   26 opening -   27 container body -   P forming position

The above detailed description of the present invention is given for explanatory purposes. It will be apparent to those skilled in the art that numerous changes and modifications can be made without departing from the scope of the invention. Accordingly, the whole of the foregoing description is to be construed in an illustrative and not a limitative sense, the scope of the invention being defined solely by the appended claims. 

I claim:
 1. A method for producing a container body comprising the following steps: punching out a disc-shaped blank (10) from a metal sheet (11), compressing the two edges (15) of the blank (10), transporting the blank (10) into a forming position (P) in a forming device (22) for forming the blank (10) into a container body (27).
 2. The method according to claim 1, characterized in that, in the forming position (P), the blank (10) is arranged between a stamp (24) and a die (23) of the forming device (22).
 3. The method according to claim 2, characterized in that, in the forming position (P), the blank (10) rests with one of its two flat sides (13) against or in the die (24) of the forming device (22).
 4. The method according to claim 1, characterized in that both edges (15) are machined simultaneously in response to the compression of the edges (15) of the blank (10).
 5. The method according to claim 4, characterized in that the peripheral surface (16) of the blank (10) rolls off of a compression tool (18) in response to the compression of its two edges (15).
 6. The method according to claim 5, characterized in that the compression tool (18) encompasses a compressed groove (19), in which the blank (10) is rolled off.
 7. The method according to claim 1, characterized in that the punching burr (14) of the blank (10) created in response to the punching is removed by means of the compression.
 8. The method according to claim 3, characterized in that the blank (10) obtains a shape, which is symmetrical opposite a central plane (S), between its two flat sides (13) by means of the compression.
 9. The method according to claim 1, characterized in that a bezel (F) is in each case formed on the blank (10) by means of the compression at its two edges (15).
 10. The method according to claim 1, characterized in that a circumferential border (V) is in each case formed on the blank (10) by means of the compression at its two edges (15). 